Polyacetylene with pyrogallol or hydrosulfite system

ABSTRACT

A process for reducing polyacetylene oxidation and embrittlement comprises treating the polyacetylene with a solution of (a) a combination of anthraquinone or an anthraquinone salt, a base and a reducing agent; or (b) pyrogallol; or (c) a hydrosulfite; and mixtures thereof. A process for isomerizing cis-polyacetylene at least partly to trans-polyacetylene comprises treating substantially cis-polyacetylene with a solution of a material which is either (a) a combination of anthraquinone or an anthraquinone salt, a base and a reducing agent; (b) pyrogallol; or (c) a hydrosulfite; and mixtures thereof and wherein the solution is at a temperature of from the freezing point to the boiling point of the solution during the treatment of the cis-polyacetylene and thereafter removing the polyacetylene which has been enriched in the trans form from contact with the solution.

This is a division of application Ser. No. 219,405 filed Dec. 22, 1980,now U.S. Pat. No. 4,356,301 issued on Oct. 26, 1982.

BACKGROUND OF THE INVENTION

Polyacetylene is prepared as disclosed in the Journal of PolymerScience, Volume 12, pages 11 through 20, Shirakawa, et al (1974), andTrans. Faraday Society, Volume 64, pages 823 through 828, Berets, et al(1968). The disclosures of these papers are incorporated herein byreference.

Polyacetylene has valuable electrical properties for a wide variety ofuses. However, when polyacetylene is prepared, within a short time afterits preparation, the polyacetylene becomes brittle and also loses aportion of its ability to acquire enhanced electrical conductivityproperties when doped. Even when a polyacetylene powder is prepared, theability of such powder to acquire enhanced electrical conductivitydecreases after a short period of time and the powder itself becomesmodified so that the preparation of formed articles from the powderbecomes difficult. One possible explanation for the loss of ability toacquire enhanced conductivity and the embrittlement of a polyacetyleneformed material, such as a film, is that the polyacetylene, whenprepared at -78° C., is in the form of cis-polyacetylene. However, it isknown that cis-polyacetylene, although generally considered stable attemperatures of from about -78° C. to 0° C., does isomerize slowly, evenat -78° C., to trans-polyacetylene. At temperatures in excess of 0° C.,isomerization of cis-polyacetylene to transpolyacetylene is accelerated.During this conversion, free radicals may be formed which may crosslinkor otherwise react with available oxygen. The reaction with availableoxygen is believed to contribute to the embrittlement of, for example, apolyacetylene film by the formation of carbonyl and hydroxyl groups.These groups disrupt the conjugation of the polyacetylene double bondsand thereby decrease the ability of the polyacetylene to acquireenhanced electrical conductivity. Whenever cis-polyacetylene isisomerized to transpolyacetylene, there will always be the formation offree radicals due to the isomerization mechanism. A discussion of thepreparation of polyacetylene films and the isomerization of such filmsis set forth in the Journal of Polymer Science, Volume 12, pages 11through 20, Shirakawa, et al (1974).

Embrittlement of a cis-polyacetylene film or formed article can bedelayed by storing the film or formed article at a low temperature (-78°C. to 0° C.) under an inert gas such as nitrogen, argon or helium.

Although it is known that the cis-polyacetylene is more flexible thanthe trans-polyacetylene, the trans-polyacetylene has greater intrinsicelectrical conductivity properties and the trans- form isthermodynamically more stable. The free radicals which may be formedduring isomerization of cis- to trans polyacetylene also trap oxygen andreduce the electrical conductivity potential of the polyacetylene(whether cis- or trans- if oxygen is present because it is believed thatthese free radicals form carbonyl and hydroxyl groups). Although, thestate of the art is still such that the formation of these free radicalscannot be eliminated, if the presence of oxygen can be eliminated, thenan aggravation of the results of free radical formation can be avoided.Thus, the problems of embrittlement and loss of electrical conductivitypotential can be alleviated.

The previous practice of avoiding embrittlement involved preparation ofcis-polyacetylene and storage of the cis-polyacetylene at lowtemperatures of from -78° C. to 0° C. under vacuum or an atmosphere ofan inert gas. Such procedures are cumbersome in any practical ambientenvironment. Therefore, the utility of polyacetylene in applicationsrequiring electrical conductivity is severely limited by the use ofthose procedures.

Any other approach to the aforesaid problem of the effects of oxygenmust take into consideration the affinity of polyacetylene for oxygen.Thus, any material which would remove oxygen from the system mustcompete with the polyacetylene for the removal of such oxygen and musthave a greater affinity for oxygen than the polyacetylene. Statedotherwise, any material which would remove oxygen must be able tocompete successfully with polyacetylene for the oxygen present.

The Journal of the American Chemical Society, Volume 46, pages 2639through 2647, L. F. Fieser (1924), discloses certain aqueous solutionswhich are useful as absorbents for oxygen in gas analysis. Thesesolutions comprise an anthraquinone salt, a base and a reducing agent.This article also discloses a potassium pyrogallate solution used forcomparative purposes and also the use of pyrogallol and the use of ahyposulfite solution. However, this article does not deal with theproblem of two substances competing for oxygen and the article isdirected to oxygen absorbents in gas analysis and does not teach orsuggest the problems set forth herein or any polyacetylene material.

When cis-polyacetylene is available and it is desired to isomerize thecis-polyacetylene, partly or wholly, to trans-polyacetylene, the problemof the presence of oxygen is also encountered in that if oxygen ispresent, then because the isomerization of cis-polyacetylene totrans-polyacetylene may involve the formation of free radicals which canreact with the oxygen to form carbonyl and hydroxyl groups and therebyto adversely affect the electrical conductivity potential, it isimportant that oxygen be excluded from the polyacetylene when it isbeing isomerized from the cis form to the trans form. Additionally, thepresence of oxygen, during isomerization, leads to more severeembrittlement of the resultant trans-polyacetylene. Oxygen must also beexcluded from trans-polyacetylene because of the adverse effect ofoxygen on the trans form which causes further embrittlement of the filmand reduction of the electrical conductivity potential. The presentmethod of excluding oxygen, namely accomplishing isomerization under aninert atmosphere, is unattractive.

It is an object of this invention, therefore, to reduce polyacetylenecrosslinking and embrittlement.

Another object of this invention is to provide a process forsubstantially preventing oxygen from contacting polyacetylene byproviding a material which will successfully compete with thepolyacetylene for the available oxygen.

Still another object of this invention is to provide a process formaintaining the electrical conductivity potential of polyacetylene.

A further object of this invention is to provide a process forisomerizing cis-polyacetylene to transpolyacetylene.

Other objects and advantages will become apparent from the followingmore complete description and claims.

DETAILED DESCRIPTION

Broadly, this invention contemplates a process for reducingpolyacetylene oxidation and embrittlement comprising the steps oftreating said polyacetylene with a solution, having a pH greater than 7,of a material selected from the class consisting of: (a) a combinationof anthraquinone or an anthraquinone salt, a base and a reducing agent;(b) pyrogallol; and (c) a hydrosulfite, and mixtures thereof.

This invention also contemplates a process for isomerizingcis-polyacetylene at least partially to transpolyacetylene comprisingtreating substantially cis-polyacetylene with a solution, having a pHgreater than 7, of a material selected from the class consisting of: (a)a combination of anthraquinone or an anthraquinone salt, a base and areducing agent; (b) pyrogallol; and (c) a hydrosulfite, and mixturesthereof, said solution being at a temperature of from the freezing pointto the boiling point of the solution during treatment of saidcis-polyacetylene, whereby the polyacetylene is enriched in the transform.

It has now been found that there are some materials and combinations ofmaterials that can act as oxygen scavengers and can compete successfullywith the polyacetylene for the oxygen. It has also been found that thesesame oxygen scavengers can be used to protect the polyacetylene duringisomerization of cis-polyacetylene to trans-polyacetylene which mayinvolve elevated temperatures and that the resultant polyacetylene whichhas been enriched in the trans form will not suffer loss of itselectrical conductivity potential due to any free radical reaction withoxygen.

The polyacetylene which is to be protected may be in the form of apowder, film or a foam-like material (hereinafter referred to as afoam). The preparation of polyacetylene foams is described in Journal ofPolymer Science; Polymer Letters Edition, Volume 17, pages 779-786,Wnek. Basically, polyacetylene foams may be prepared by polymerizingacetylene gas in the presence of a Ziegler-Natta type catalyst atconcentrations that are less than normally employed when forming a film.After the polyacetylene gel is obtained, solvent is removed under vacuumfrom the gel and the solvent is replaced with benzene. The benzene inthe gel is then frozen, and the benzene is then sublimed to prepare thepolyacetylene foam.

Regardless of the form of the polyacetylene, the polyacetylene useful inthis invention is undoped. The term "doped" means that the polyacetylenehas been subjected to a treatment to increase electrical conductivityproperties as described in U.S. Pat. No. 4,222,903. The polyacetylenesuseful in this invention have not been treated to affect the electricalconductivity properties of the polyacetylene. It is possible however,that the polyacetylene may have some small degree of doping whichresults from the method of preparation of the polyacetylene and suchpolyacetylene is also considered undoped.

In the process of this invention, the oxygen scavenger is present insolution in a concentration of at least about 0.01 molar and preferablyfrom about 0.01 M to about 10 M. If the concentration of the oxygenscavenger is less than 0.01 molar, then the polyacetylene will not beadequately protected during prolonged storage.

Although the oxygen scavenger may be present in excess of 10 molar,there is no particular advantage in using such large amounts.

For purposes of the combination of anthraquinone or an anthraquinonesalt, a base and a reducing agent, the anthraquinone salt may beconsidered as the active component and when this combination is used,the molar amounts set forth above which pertain to the concentration ofoxygen scavenger present shall be interpreted to refer to theconcentration of anthraquinone or anthraquinone salt although the baseand reducing agent are also necessary.

Among the oxygen scavengers which may be used because they competesuccessfully with the polyacetylene film for the available oxygen are acombination of anthraquinone or an anthraquinone salt, a base and areducing agent; pyrogallol; and a hydrosulfite solution.

When a combination of anthraquinone or an anthraquinone salt, a base anda reducing agent is present, there are certain interrelationshipsbetween the anthraquinone or anthraquinone salt, base and reducing agentwhich will govern the amount of base and reducing agent present.

When scavenging oxygen, the anthraquinone is reduced and it is thisreduced form of the anthraquinone or anthraquinone salt which isresponsible for preferentially scavenging oxygen. When the anthraquinoneor anthraquinone salt is reduced, certain acidic byproducts are formed.If these acidic byproducts are allowed to remain in the scavengingsolution, then eventually, the pH of the solution will be below 7 andthe solution will no longer be as effective in scavenging oxygen than asolution having a pH greater than 7. When the reduced anthraquinonescavenges oxygen, it is again converted to the anthraquinone or theanthraquinone salt. The base, which is present, functions to remove theacidic byproducts from the solution. However, the base may not bepresent in an amount which exceeds 50 times the number of moles ofanthraquinone present. If the amount of moles of base exceeds 50 timesthe amount of anthraquinone present, then the solution will not be aneffective oxygen scavenger.

The reducing agent may be present in any desired amount. Although it ispreferred that the moles of base present be at least equivalent to thenumber of moles of reducing agent present, there may be an excess ofreducing agent present. If there is an excess of reducing agent present,then, even when the supply of base is exhausted, the reducing agent willstill function to reduce the anthraquinone or anthraquinone salt to aform which scavenges oxygen although there will then be a build up ofacidic byproducts. When acidic byproducts are present in an amount suchthat the pH of the solution is less than 7, the solution will no longerbe as effective as an oxygen scavenging solution than a solution havinga pH greater than 7.

Thus, from the above, it is apparent that the number of moles of basepresent will vary up to 50 times the number of moles of anthraquinone oranthraquinone salt present and that, although it is preferred that thenumber of moles of reducing agent present equal or be less than thenumber of moles of base present, the number of moles of reducing agentpresent may be more or less than the number of moles of base present. Ina typical useful scavenging solution, the mole ratio of anthraquinone oranthraquinone salt to base to reducing agent may be from 1 to 28 to 7,respectively.

Additionally, it is also preferred that the reducing agent be present ina large excess, including a saturated solution of the reducing agent.

Typically, for each mole of anthraquinone or anthraquinone salt present,a useful amount of base present will be from about 1 mole to about 50moles and a useful amount of reducing agent present will be from about 1mole to about 50 moles.

Among the anthraquinone salts which may be used are anthraquinoneβ-sulfonate, sodium anthraquinone-β-sulfonate, sodium anthraquinoneα-sulfonate; disubstituted anthraquinone sulfonic acid salts such as the1,5-disulfonic acid salts and the 2,6 disulfonic acid salts and thelike. Additionally, anthraquinone itself may also be used.

The base which is used may be a nitrogenous base, including anitrogenous organic base, or metal hydroxide. The metal hydroxide whichmay be used may be any metal hydroxide such as sodium hydroxide,potassium hydroxide, calcium hydroxide, ammonium hydroxide and the like.The nitrogenous base may be a primary, secondary or tertiary amine or aquaternary ammonium hydroxide, and the like. Exemplary of suchnitrogenous bases are ethylene diamine, tetraethylene pentamine,n-propylamine, 2-hexylamine, tetra-n-butyl ammonium hydroxide, pyridine,diazabicyclo[2.2.2.] octane, and the like.

The reducing agent which is used may be any water soluble or organicsolvent soluble reducing agent such as sodium dithionite, sodiumborohydride, potassium borohydride, sodium cyanoborohydride; and thelike.

Any water or organic solvent soluble hydrosulfite may be used such assodium or potassium hydrosulfite, and the like despite the fact thatsodium hydrosulfite itself tends to be unstable at a temperature inexcess of 60° C. During isomerization of cis-polyacetylene totranspolyacetylene, temperatures in excess of 60° C. may be used.

The solution used as an oxygen scavenger should be at a pH of from about7 to about 14. If the pH of the solution is less than 7, then thesolution will not be maximally effective in preferentially scavengingoxygen.

The temperature of the solution may vary widely from the freezing pointof the solution to the boiling point of the solution.

The solvent for the oxygen scavenger may be water and may include aco-solvent such as ethylene glycol, methyl alcohol, ethyl alcohol,dimethyl sulfoxide, tetrahydrofuran, dimethyl formamide, acetonitrile,glyme, diglyme, and the like, which are water miscible. The use of aco-solvent is often advantageous because it enables the use oftemperatures in excess of the boiling point of the aqueous solutionwhich contains only water as the solvent for the oxygen scavenger. Theterm "aqueous solution," as used herein, includes the use of such watermiscible co-solvents.

Although aqueous solutions of oxygen scavengers are useful in practicingthis invention, it is sometimes preferable to employ an organic solutionof the oxygen scavenger. Because the organic solvent used will generallyhave a lower freezing point than water, employment of an organic solventenables the polyacetylene to be protected at a lower temperature thandoes water. Treatment of polyacetylene at a lower temperature isadvantageous, when the polyacetylene contains at least somecis-polyacetylene and it is desired to maintain the amount ofcis-polyacetylene present, because of the tendency of cis-polyacetyleneto isomerize to trans-polyacetylene at higher temperatures.Additionally, when employing water as a solvent, if the temperature ofthe solution is too low, there is the danger that the oxygen scavenger,which is dissolved in the water, may precipitate out of solution and thevalue of any precipitated oxygen scavenger would then be lost.

Any organic solvent may be used which will dissolve the desired amountof oxygen scavenger, or combination thereof. Among such organic solventsmay be mentioned dimethyl formamide, dimethyl acetamide, N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, sulfolane, glyme,diglyme, and the like.

When cis-polyacetylene is being converted, partly or wholly, totrans-polyacetylene, elevated temperatures are generally used although atemperature of from about -78° C. to about 250° C. may also be used. Themaximum temperature used is limited only by the boiling point of thesolution system used. The temperature used may be increased by the useof greater than atmospheric pressure when isomerizing cis-polyacetyleneto trans-polyacetylene.

When protecting a polyacetylene from the effects of oxygen, thepolyacetylene in the form of a powder, foam or film is generallyimmersed in the protective oxygen scavenging solution until such time asit is desired to use the polyacetylene. In a typical protectiveoperation, polyacetylene is immersed in a solution of the oxygenscavenger and the vessel containing the polyacetylene is then sealed toexclude oxygen.

When isomerizing cis-polyacetylene, partly or wholly to the trans form,such isomerization process may be accomplished by immersing thecis-polyacetylene in a protective solution which is at a temperature offrom about -78° C. to about 250° C. and preferably from about 0° C. toabout 250° C. and maintaining the temperature of the polyacetylenecontaining protective solution until the desired amount of trans isomerhas been obtained as determined by infrared analysis.

The polyacetylene being isomerized may be composed of 100%, by weight,of cis-polyacetylene or may be composed of, for example, 25%, 50% or 75%or more of cis-polyacetylene and, depending upon the amount ofcis-polyacetylene orginally present and the desired product, theisomerization to trans-polyacetylene may proceed until, for example, theisomerized product is composed of from about 10% transpolyacetylene toabout 100% trans-polyacetylene.

Subsequent to the protection of the polyacetylene with the oxygenscavenging solution or the conversion of cis-polyacetylene, partly orwholly, to trans-polyacetylene, the polyacetylene may be doped toincrease its electrical conductivity properties.

In order to more fully illustrate the nature of this invention and themanner of practicing the same, the following examples are presented.

EXAMPLE 1

A solution is prepared by mixing in a beaker containing one liter ofwater, 200 g. of potassium hydroxide; 150 g. of sodium dithionite; and20 g. of sodium anthraquinone-beta sulfonate. A deep red solution formsimmediately upon the addition of the anthraquinone salt. A strip ofcis-polyacetylene film (one inch by 3 inches by 4 mils) is placed in ajar and the solution is added to the jar so that the polyacetylene filmis completely immersed in the solution. About 250 cc. of airspace isleft in the jar. The jar is then closed, but not hermetically sealed,thereby allowing some air to leak into the jar. The jar is allowed tostand for ten months at room temperature. At the end of ten months thefilm is removed from the solution and it is sufficiently flexible to bedoubled in half without breaking. In contrast with this, bothcis-polyacetylene and trans-polyacetylene film exposed directly to airfor less than one week, crumbles upon handling.

EXAMPLE 2

A solution of alkaline pyrogallol is prepared by mixing 150 g. ofpyrogallol with 1,350 milliliters of a potassium hydroxide solutionhaving a specific gravity of 1.55 and 150 milliliters of water.

A second solution is prepared in the manner of Example 1.

Aqueous solutions containing 20% by weight of oxygen scavengers areprepared. These aqueous solutions are as follows:

(1) Irganox 1076 (octadecyl 3-(3,5-di-tertiary-butyl-4-hydroxyl phenyl)propionate.

(2) Irgastab 2002 a hindered phenol containing nickel phosphonate andhaving the formula Ni-bis[o-ethyl(3,5-di-tertiary-butyl-4-hydroxybenzyl)]

(3) Cyanox 1729 a hindered phenol containing sulfur and manufactured byAmerican Cyanamid Company. (4) Cyanox 2246, a hindered bisphenol havingthe formula 2,2'methylene bis(6-tert-butyl-4-methyl phenol).

(5) Cyanox 1735 an alkylidene polyphenol manufactured by AmericanCyanamid Company.

(6) Methyl ether of hydroquinone dissolved in tetrahydrofuran.

The solutions are all placed in jars and about 250 cc. of airspaceremains in each jar. Freshly prepared strips (one inch by three inchesby 4 mils) of cis-polyacetylene film are immersed in each of thesolutions and the jars are then closed but not hermetically sealed.After one week in the closed, air-containing jars, the films which areimmersed in the Irganox 1076; Irgastab 2002; Cyanox 1729; Cyanox 2246;and Cyanox 1735 were all embrittled and crumbled on handling.

After one month, the film in the methyl ether of hydroquinone is alsoembrittled and crumbles on handling.

The films immersed in the solution of Example 1 and in the alkalinepyrogallol solution remain flexible after 8 months in the jar and showno signs of embrittlement.

EXAMPLE 3

Cis-polyacetylene film is prepared by the method of Shirakawa, et al,Journal of Polymer Science, Polymer Chemistry Edition, Volume 12, pages11-20 (1974). The cis-polyacetylene film is then thoroughly washed withdry toluene at a temperature of -78° C. and under a nitrogen atmosphere.The film measures 12 inches by 10 inches and is from 2 to 4 mils thick.The film is immediately immersed in a vessel containing the solutionprepared as in Example 1. The vessel is then heated to 100° C. and heldthere for 72 hours. At the end of the 72 hours, a section of the film isremoved and analyzed by infrared spectroscopy for isomer content. Thefilm is more than 95% trans-polyacetylene. Additionally, the film isfree of carbonyl functional groups as determined by infraredspectroscopy. Additionally, the film remains flexible.

By contrast with the above, a cis-polyacetylene film is prepared asdescribed above and is placed in a vessel and is heated in an airatmosphere at 200° C. for 11/2 hours. The resultant film has a highcontent of transpolyacetylene and is extremely brittle and crumbles whenhandled.

EXAMPLE 4

Polyacetylene powder is prepared by the method disclosed in Berets, etal, Trans. Faraday Society, Volume 64, pages 823 through 828. The powderis immersed in a solution prepared in the manner of Example 1 andremains there for four days. The powder is thereafter removed and washedwith water and methanol and then dried in vacuo. The powder is thencompressed into a disk having a 3 cm. diameter and being 0.4 cm. thick.This disk is then doped with iodine vapor as disclosed in U.S. Pat. No.4,222,903.

A second disk is prepared in the manner of the first disk except thatthe powder, from which the second disk is prepared is not immersed inany protective solution and the powder is exposed to the atmosphere forfour days prior to preparing the disk.

This second disk is also doped with iodine vapor in the manner of dopingof the first disk.

The electrical conductivity of both disks is measured using theprocedure set forth in ASTM F-43, as applied to a polyacetylene film.The conductivity is calculated from the test results. The disk made fromthe powder which had been immersed in a protective solution for fourdays, exhibits superior conductivity properties when compared to thepolyacetylene disk made from unprotected powder.

EXAMPLE 5

In a flask is added 5.0 grams of sodium borohydride dissolved in 50milliliters of dry N,N dimethyl formamide containing one gram of sodiumanthraquinone-beta-sulfonate. 5.0 grams of sodium hydroxide is thenadded to the flask and a deep red-purple color results. A 5 cm. by 5 cm.by 3 to 4 mil thick section of cis-polyacetylene (greater than 70% cisisomer content) film is immersed in this solution. After 10 months, thefilm is removed, washed with water, dried and treated with a variety ofP-type dopants to produce a film conductivity which exceeds 10³ OHM⁻¹cm⁻¹. The film remains sufficiently flexible to be doubled in halfwithout breaking. By contrast with the above, a section of film which isnot protected by immersion in the oxygen scavenging solution, and isallowed to remain exposed to air, is embrittled within one week.

EXAMPLE 6

The procedure of Example 5 could be repeated except that anthraquinonecould be used in place of the sodium anthraquinone beta sulfonate. Thesolution will be effective in protecting the cis-polyacetylene.

EXAMPLE 7

The procedure of Example 5 could be repeated several times except thatthe solvent used would be replaced. The solvent which could be used inplace of the solvent of Example 5 are N-methyl pyrrolidone, dimethylacetamide, and ethylene glycol dimethyl ether. In each instance, goodresults would be obtained.

The process of this invention is not only useful in isomerizingcis-polyacetylene, wholly or partially, to trans-polyacetylene but isalso useful in protecting undoped polyacetylene after it has beenprepared but before it has been doped. For example, polyacetylene film,powder or foam may be immersed in a protective solution and stored thereuntil it is desired to use or dope the polyacetylene. At that time, thepolyacetylene is removed from the protective solution and, if thepolyacetylene is to be doped, washed free of the protective solution andthen doped. The protective solution may also be used to shippolyacetylene by immersing the polyacetylene in an envelope containingthe protective solution and sealing the envelope.

While this invention has been described in terms of certain preferredembodiments and illustrated by means of specific examples, the inventionis not to be construed as limited except as set forth in the followingclaims.

I claim:
 1. A process for reducing polyacetylene oxidation andembrittlement comprising the steps of treating said polyacetylene with asolution having a pH greater than 7, of a material selected from theclass consisting of pyrogallol, sodium hydrosulfite, and potassiumhydrosulfite.
 2. A process according to claim 1 wherein pyrogallol ispresent in a concentration of at least about 0.01 molar.
 3. A processaccording to claim 1 wherein said hydrosulfite is present in aconcentration of at least about 0.01 molar.
 4. A process according toclaim 1 wherein the solvent for said material is an aqueous solvent. 5.A process according to claim 1 wherein the solvent for said material isan organic solvent.
 6. A process according to claim 5 wherein saidorganic solvent is substantially anhydrous.
 7. A process according toclaim 1 wherein said polyacetylene is a film.
 8. A process according toclaim 1 wherein said polyacetylene is a powder.
 9. A process accordingto claim 1 wherein said polyacetylene is a foamed material.
 10. Aprocess according to claim 1 wherein the solvent for said material is acombination of water and a water miscible cosolvent.
 11. A process forisomerizing cis-polyacetylene at least partially to trans-polyacetylenecomprising treating said polyacetylene with a solution, having a pHgreater than 7, of a material selected from the class consisting ofpyrogallol, sodium hydrosulfite, and potassium hydrosulfite, saidsolution being at a temperature of from the freezing point to theboiling point of the solution during treatment of said cis-polyacetylenewhereby the polyacetylene is enriched in the transform.
 12. A processaccording to claim 11 wherein said cis-polyacetylene is in the form of afilm.
 13. A process according to claim 11 wherein said cis-polyacetyleneis in the form of a powder.
 14. A process according to claim 11 whereinsaid cis-polyacetylene is in the form of a oamed material.
 15. A processaccording to claim 11 wherein said cis-polyacetylene being isomerized isat least 25% cis-polyacetylene.
 16. A process according to claim 11wherein said cis-polyacetylene is isomerized to at least 25%transpolyacetylene.